Urea-formaldehyde reaction products and methods for producing the same



Patented Aug. 20, 1946 UCTS AND METHODS FOR PRODUCING THE SAME Mortimer '1. Harvey, South Orange, N. 1., and Solomon Caplan, New York, N. Y., assignors to Harvel Research Corporation, a corporation New Jersey No Drawing.

1 It is an object of the present invention to produce stable aqueous solutions of the urea-formaldehyde type of condensation product.

The present application is a continuation in part of our copending application Ser. No. 294,-

480, filed September 12, 1939.

' When employing thermosetting resins for such purposes as impregnation of porous compositions, as coatings for laminating purposes, for plywood adhesives, and the like, it is usually necessary to utilize solutions of such thermosetting resins. Organic solvents have almost universally been employed for the purpose of obtaining such solutions and in the subsequent operations of converting the thermosetting resin to the infusible Application October 23, 1942. Serial No. 463,132

2 Claims. (Cl. 260-69) 2 Example Tertiary butyl urea "grams" 11d Formaldehyde solution (37 /2% do 10o Ammonia solution (26) cc 2.7

This mixture was refluxed at boiling temperature for one hour and allowed to cool.

Example 2 Tertiary butyl urea 'grams 116 Formaldehyde solution (SW/ do 160 Ammonia solution (26") cc 2.7

This mixture was refluxed at boiling tempera state, the organic solvents have been driven off and lost. It would therefore be desirable to use water as the solvent for the thermosetting resin.

Such water soluble thermosetting resins have been developed in the nature of urea-formaldehyde condensatiomproducts. The great disadvantage of such aqueous solutions of urea-formaldehyde resins has been their short storage life. This objection has long been recognized and various means of overcoming it have been proposed. Thus, for example, in an article published in Industrial and Engineering Chemistry, vol. 31, page 673 (1939), the authors have drawn attention to this failing of aqueous Solutions of urea-formaldehyde resins and have proposed the addition of glycols for the purpose of stabilizing the solutions. Owing to the water solubility of the glycols, the finished products, even after conversion to the infusible state, have rather poor water resistance.

It is further an object of the present invention to produce stable aqueous solutions of the urea.- formaldehyde type of resin in which'the stabilizing agent is itself-capable of reacting with the formaldehyde with the production of thermos'etting resins havin high moisture resistance.

The present invention i based upon the find- 1 ing that aqueous solutions of formaldehyde condensation products of the monotertiary-alkyl ureas are extremely stable and that mixtures of urea with monotertiary-alkyl ureas, upon reaction with formaldehyde, produce stable aqueous solutions of thermosetting resins. od of preparing such tertiary-alkyl ureas, reference is made to our Patent 2,247,495, issued July 1, 1941.

As illustrative examples of the formaldehyde condensation products of the mono-tertiary-alkyl ureas, the following are given:

For the methture for one hour and allowed to cool.

Example 3 v Tertiary butyl urea "grams" 116 Formaldehyde solution (37 /2%) do 240 Ammonia solution (26) cc 2.7 This mixture was refluxed at boiling temperature for one hour and allowed to cool.

Examples 4, 5 and 6 The above series of experiments was repeated but instead or 116 grams of tertiary butyl urea, grams of tertiary amyl urea was used.

Examples 7, 8 and 9 Examples 1, 2 and 3 were repeated but with the use of 144 grams of tertiary hexyl urea instead of the 116 gram of tertiary butyl urea.

In all of the above examples the resulting aqueous solutions showed substantially no increase in viscosity after months of storage at room temperature.

Aqueous solutions of the formaldehyde condensation products where then mixed with aqueous solutions of freshly prepared urea-formaldehyde condensation products and it was found that the resulting combined solutions were stabilized to a degree varying with the proportion of the tertiary alkyl urea-formaldehyde condensation product added.

, Instead of performing two separate formaldehyde reactions, one with urea and the other with the tertiary alkyl urea and then mixing the products, the more economical procedure would consistin mixing urea with the tertiary alkyl ureas and reacting upon that mixture with formaldehyde. This was tried and found to produce stabilized solutions, the degree of stability again being dependent upon the amount of tertiary alkyl urea added to the urea.

' The following examples are presented for illustratlve purposes. 1

' Ammonia solution (26) ....-cc-- I Example I Urea g ams" 60 Formaldehyde solution (37%%) do -..--200 Ammoniasolution (26) --cc 2.3

This was refluxed at boiling temperature for one hour and then permitted to cool. The solution became a non-flowing gel within two weeks of storage at room temperature.

Example 11 Urea g ams.. 60 Tertiary butyl urea -do Formaldehyde solution (37%%) do- 200 Ammonia solution (26) ..-cc-.. 2.3

This solution was refluxed at boiling temperature for one hour and permitted to cool. Upon standing at room temperature, it became a non- This mixture was refluxed at boiling temperature iorone hour and allowed to cool at room temperature. The solution gelled to a non-flowing state I I after four weeks at room temperature.

Example 13 Urea g ams Formaldehyde solution (37%%)-- do 275 Ammonia solution (26) .cc. 3

This solution was refluxed for one hour at bolling temperature and allowed to cool. The solu- This solution was refluxed at boiling temperature tion gelled to a non-flowing state after two weeks on standing at room temperature.

. Erample 14 I v Urea grams..- 60 Formaldehyde solution (37 $6 do-;.- 275 Tertiary butyl urea --do-.. 18 Ammonia solution (26) -..cc-.. 3

This solution was refluxed for one hour at.boiling temperature and allowed to cool. There was no change in viscosity after two months standing at room temperature.

This solution was refluxed for one hour at boil- I ing temperature and allowed to cool. There was no change in viscosity after two' months standing at room temperature. 7

r I Example 16 3 'Urea g ams 80 Tertiary hexyl urea do..-- 18 "Formaldehyde solution (37%%)- ..do..-- 275 Ammonia solution (26) cc This mixture was refluxed for one hour at boiling temperature and allowed to cool. There was no Example. 15 Urea g grams- Tertiaryamyl urea -..do... 18 Formaldehyde solution (37 Vz%) ...do.... 27;

3 change in viscosity after two months standing at room temperature.

Example 17 Urea g ams" 60 Formaldehyde solution (37%%) do. 120

for one hour and allowed to cool. The solution gelled to a non-flowing state within two weeks at room temperature. I

- Example 18 Urea ams" Tertiary butyl urea ..do 12 Formaldehyde solution (37%%) ..do 120 Ammonia solution (26). cc 1.4

This mixture was refluxed for one hour at boiling temperature and allowed to cool. There was only a slight increase in'viscosity after two months standing at room temperature. p

Example 19 Urea g ams" 60 Tertiary amyl urea --do-.. 12 Formaldehyde solution (37%%) do 120 Ammonia solution (26) cc..- 1.4

This mixture was refluxed for one hour at boiling temperature and allowed to cool. There was only a slight increase in viscosity after two months standing at room temperature.

Example 20 Urea grams.. 80 Tertiary hexyl urea ..-do 12, Formaldehyde solution (37%%) -..do.....- 120 Ammonia solution- (26") -cc 1.4

This mixture was refluxed for one hour at bolling temperature and allowed to cool. There was only a slight increase in viscosity after two months standing at room temperature.

In each ofthe above examples where mixtures of urea and tertiaryurea were employed, the solution of the reaction products, upon acidiflcation and heating at 0., produced intusible fllms which had good water resistance. In addition to the urea and substituted ureas disclosed in the preceding examples, other substances may be present for the purpose of modiiying the properties or the resins obtained and in particular those addition substances which possess the property of reacting with formaldehyde with the production or water soluble condensation products. Such a substance, for example, would be melamine.

As previously stated, the aqueous solution oi the reaction products or formaldehyde with the mixtures of urea and tertiary alkyl ureas in the proportions of from ten to thirty per cent of the alkyl urea, based on theweight or the urea. are suitable for 1 the coatings, the like.

Although the present invention is particularly suited for the production or aqueous solutions of laminated products. plywood veneers and resins, there are occasions when the solutions or these resins in organic solvents are desirable, particularly when it is desired to incorporate such resins into oleoresinous varnishes. For such pur- 5 pose, the aqueous solutions obtained in accordance with the preceding xamples are acidifled and then shaken with such solvent as butyl alcohol, a'mylalcohol. octyl alcohol or combinations or these. It has been found that the solutions in organic solvents or the joint resins disclosed in this invention are capable of dilution with appreciably greater proportions of mineral sol-V vents,-such as the various paint thinners obtained from petroleum, than is possible with similar so- Ammonia solution (26)- -..cc 1.4 75 ,iution or urea-formaldehyde condensation prod production or water-resistant sorhent nllers,

\ottheresinsorwiththe claimanddesinetoproteot ucts reparedintheahsenceoithetertiarraikyi to prepare moidins' powders solutions or the joint, resins inthisinventionbytheadditionoi absuoh as wood hour. to the aqueous solutions or the ter either y D lution so! suction and heat or bymeans oihotmixinsroiis. Acidicaaentsmay be incorporated either with the aqueous solution iinai molding powder.

ureas.

It is aiso possible from the aqueous disclosed It has been found that have a ionser storase iii'e similar moidins compositions prepand from the straisht urea-formaldehyde condensation prod- Having thus described our invention, what we hyletterlratent is:

resins and removal ot-the wa-v.

suchmoidins powders thanisthecasewith- 1. The method of produoinl I solution of urea-iormaidehriie condensation prodnot which comprises heat moiesoiaqueousi de-withamixture containing one moie of urea a mono-tertiaryi-urea havina from tour to six carbon-atoms in the'aikyi group eq al to fromtentothirtyperoentoitheurea.

2. A composition oi matter comprisins a heatreaction product of iron; one to three moles of aqueous iormaidehyde with a mixture containins one moleioi urea and an amount of a mono-tertiary-aikyi-urea havinl'iroin four to six carbon atoms in the ai yi sroupequ l thirtypercent oi theurea.

uonkrnm '1'; mm. sonouon astahisaqueous' totromtento' 

